1. Field of the Invention
The invention relates to a gas intake device for letting the said gases into the cylinder head of a motor vehicle combustion engine. The term “gases” is to be understood to mean air or a mixture of air and exhaust gas, to which liquid and/or gaseous fuel may have been added.
2. Description of the Related Art
A motor vehicle combustion engine comprises a combustion chamber, generally formed by a plurality of cylinders, in which a mixture of oxidant and fuel is burnt in order to generate engine work. The oxidant comprises air, which may or may not be compressed according to whether or not the engine is fitted with a turbocharger. The air may also be mixed with exhaust gases: these are then known as EGR (exhaust gas recirculation) gases. The gases admitted to the combustion chamber are termed inlet gases.
The inlet gases are received at an intake manifold, the English-language term “intake manifold” being widely understood by all those skilled in the art. The manifold is mounted on the cylinder head of the combustion chamber, at the inlet to the cylinder's. The gases may be cooled, partly cooled, or uncooled, depending on the engine speed. There are therefore two pipes leading into the manifold: one carrying the inlet gases directly into the manifold, and the other carrying them indirectly via a heat exchanger that can be used to cool the gases passing through it or, in some instances, to heat them.
Heat exchangers of the prior art are housed in a casing, generally made of plastic. Aside from the function of housing the heat exchanger, the casing is often designed also to form the inlet box and/or the outlet box of the heat exchanger. The casing also generally supports a certain number of other items such as, for example, parts of couplings, valves, the intake manifold, an exhaust gas intake module, etc., depending on the build of the engine.
Aside from these requirements to support things, the casing is subjected to pressure loadings associated with the flow of the compressed inlet gases. The lid of the casing in particular covers the entire casing and is subjected to all the pressure. What is more, this casing is subjected to the vibration generated by all the items it supports.
A casing such as this has therefore to be stiffened in order that it should not “inflate” under the pressure loadings or deteriorate on account of the vibration. Such stiffening is expensive and means making the casing heavier.
Furthermore, one of the objectives ever pursued by engine manufacturers is to make the inlet gas intake device as compact as possible.